Audio Pitch Compensation in Video Trick Mode Playback
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Solution Overview
Problem
Conventional DVD players distort audio during trick mode playback, making it unnatural and unintelligible when video is played at faster or slower speeds, as audio frequencies shift, leading to annoying high-pitched speech at fast speeds and unacceptable low-frequency sounds at slow speeds, prompting the need for improved audio processing during video trick modes.
Innovation Solution
A method and apparatus that decodes digital audio samples and uses a karaoke processor to adjust the audio pitch by dropping or repeating samples at rates corresponding to the trick mode speed, with a digital-to-analog converter generating an audio playback signal, and shifting the pitch to maintain natural sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If video playback speed is increased during trick mode, then video search efficiency is improved, but audio pitch shifts to higher frequencies making speech unintelligible and annoying
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the audio playback rate to match the video trick mode speed multiplier. When video is played back at accelerated speeds during trick mode, the audio playback rate is correspondingly increased, preventing pitch distortion and maintaining speech intelligibility while preserving the improved video search efficiency.
2Measurement precision
If video playback speed is decreased during trick mode, then detailed examination of video sequences is improved, but audio produces lower frequency wobbling sounds that are unacceptable to listeners
Solution Approach 1:
The patent applies parameter changes by synchronizing audio playback rate adjustments with video speed changes during trick mode. When video is slowed down for detailed examination, the audio playback rate is correspondingly reduced, preventing the harmful lower frequency wobbling sounds while maintaining the enhanced detail examination capability.
3Object-affected harmful factors
If audio is muted during trick mode playback, then audio pitch distortion is avoided, but audio content of interest is lost
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the audio playback rate to match the video trick mode speed multiplier, thereby eliminating the need to mute audio during trick mode playback. This approach preserves both speech intelligibility and music quality while maintaining audio content that may be of interest to the user.
Data Source
AI summary
The invention concerns a method and apparatus for audio content playback during fast forward playback video trick modes. A storage medium reader is provided for reading coded digital data from a storage medium such as a DVD. The coded digital data comprises a video programming and a corresponding audio programming. A decoder decodes from a portion of the digital data comprising the audio programming a plurality of digital audio samples corresponding to a selected portion of the video programming. Subsequently, an audio processor key shifts a playback audio pitch associated with the audio samples to compensate for the higher pitched audio associated with the fast forward video playback mode.